Local Anesthetics Flashcards Preview

Pharmacology II > Local Anesthetics > Flashcards

Flashcards in Local Anesthetics Deck (31):
1

Esters

-cause more hypersensitivity reactions
-only 1 letter "i"

2

Ester durations and potency

Short: Procaine (1)
Long: Tetracaine (16)
Topical/Surface: Benzocaine, cocaine (2)

3

Amides

-2 letter "i"s

4

Amides duration and potency

medium: lidocaine (4), mepivacaine (2)

Long: bupivacaine (16), ropivacaine (16)

5

Esters: Onset and duration

1. Procaine:
onset: 2-5min
duration: 25 min to 1 hour

2. Tetracaine
onset: <15 min
duration: 2-3 hours

6

Amides: onset and duration

1. Mepivacaine
onset: 3-5 min
duration: ~1hr

2. Bupivacaine
onset: 5 min
duration: 2-4 hrs

3. Lidocaine
onset: <2min
duration: 30min - 1hr

4.Ropivacaine
onset: 10-30min
duration: ~30min

7

Local anesthesia MOA

block voltage-dependent sodium channels of excitable membrane from sending sensory info to the CNS

8

Which form of local anesthetic is better/faster at crossing the lipid membrane to reach the cytoplasm receptor site?

Non-ionized form

9

Which form of local anesthetic is the more effective blocking entity once inside the axon?

Ionized form

10

What effect does sodim bicarbonate have when added to a local anesthetic?

1. Accelerates the onset of action

2. Decreases burning sensation

11

What effect does adding epinephrine (alpha agonist sympathomimetic vasoconstrictor) to a local anesthetic?

prolongs duration

(long acting don't need this - bupivicaine, ropivicaine, tetracaine and neither do topical local anesthetics)

12

What is the difference in esters and amides when it comes to metabolism?

Esters - metabolized in the blood by plasma cholinesterases (very rapid)

Amides -metabolized by liver (so, higher risk of liver toxicity with liver dysfunction)

13

What type of fiber would be most easily blocked?

a small myelinated fiber

14

What type of fiber would be most difficult to block?

a large unmyelinated fiber

15

Which type of fiber is hardest to block?

Type A - Alpha (proprioception, motor)

16

Which type of fiber is easiest to block?

Types B, C and Type A - delta (pain, temperature)

17

Which would be blocked first a medium myelinated fiber or a small unmyelinated fiber?

the myelinated fiber

18

A-alpha fiber

-muscle proprioception
-Largest fiber type
-myelinated

19

A-beta fiber

-Second largest fiber
-Touch
-myelinated

20

A-delta fiber

-3rd largest fiber
-pain and temperature
-myelinated

21

C-nerve fiber

-Not myelinated
-pain, temperature, itch
-Small fiber

22

Sequence of nerves to be blocked

1. Sympathetic
2. Temperature
3. Pain
4. Light touch
5. Motor

23

Epidural block

-local anesthetic extradurally

24

Caudal block

-epidural block in the caudal canal via the sacral hiatus

25

Spinal block

injection into cerebrospinal fluid in the subarachnoid space

26

Why is bupivacaine banned by the FDA in obstetrics for epidural anesthesia?

cardiotoxicity

27

How can you tell local anesthetics with and without epinephrine by the label on the bottle?

red label if it contains epi

28

Amides local anesthetics

Pharmacokinetics: hepatic metabolism

-bupivacaine is most likely to cause heart problems
-CNS effects (light headed, sedation, restlessness, nystagmus, tonic-clonic convulsions

29

Ester local anesthetics

Pharmacokinetics: rapid metabolism by plasma esterases

-Metabolites can cause antibody formation

ex. Benzocaine, cocaine, procaine, tetracaine

30

Prilocaine: ADE

can convert hemoglobin to methemoglobin

31

What medication is given to someone having a convulsion due to anesthetic toxicity?

Diazepam IV (Valium)